1. Filed of the Invention
The present invention relates to an active energy ray curable coating composition which is to be cured by irradiation with active energy rays to provide a transparent coating film having favorable abrasion resistance and excellent stain resistance against grease stains, particularly excellent removability of fingerprints attached to its surface. Further, the present invention relates to a molded product comprising a glass or plastic substrate and a coating film made of a cured product of the coating composition formed on the surface of the substrate, having excellent abrasion resistance and stain resistance against grease stains over a long period, particularly excellent fingerprint removability.
2. Discussion of Background
To mirror-finished metal plates, or inorganic glass show windows, showcases, opening materials of automobiles, antireflection films, optical filters, optical lenses, liquid crystal displays, CRT displays, projection televisions, plasma displays, EL displays, optical disks, etc., grease stains such as fingerprints, sebum, sweat and cosmetics are likely to attach depending upon their environment in many cases. Such grease stains once attached are hardly removed, and particularly on optical members equipped with an antireflection film, the attached stains stand out and are thereby problematic. As a means to solve such a problem due to attachment of grease stain, various techniques have been proposed to form a stain resistant layer having such a function that grease stains are less likely to be attached thereto, and even if they are attached, they are likely to be wiped off, on the surface of an optical member. In an optical member having a stain resistant layer on its surface, the stain resistant layer located as the outermost layer is likely to be scarred when the stains are wiped off.
In JP-A-2002-248703, a coating composition having a silicone compound or a fluorine-containing compound added as a lubricity-imparting agent so as to impart abrasion resistance and lubricity to a cured product layer of a molded product with a coating, is used. However, the silicone compound or the fluorine-containing compound as disclosed in the above publication has a low affinity with a matrix resin, and thus it is likely to bleed out from the surface of the matrix resin when the composition is coated, thus impairing transparency at a coated portion. Further, addition of a silicone compound as a lubricity-imparting agent can not provide adequate stain resistance.
JP-A-11-293159 discloses a hard coating agent for an optical recording medium containing a fluorine type surfactant. However, a hard coat layer containing the fluorine type surfactant is insufficient in abrasion resistance, and in order to impart stain resistance, two kinds of fluorine type surfactants, i.e. a crosslinked fluorine type surfactant and a non-crosslinked fluorine type surfactant, are required.
JP-A-2000-191668 discloses a stain resistant composition containing a fluorine-containing compound having an alkoxysilane structure at its terminal by means of a carbamate linkage and fine particles of an inorganic compound or an organic compound. However, adhesive properties of the stain resistant composition are attributable to linkage of an alkoxysilane contained in the composition to a layer comprising an inorganic compound such as silicon dioxide, and thus when no inorganic compound layer is present on the substrate surface, even if stain resistance may be temporarily obtained, no long-term stain resistance can be obtained. Further, the stain resistant composition also has only stain resistance but has no mechanical strength, and its surface is relatively likely to be scarred. Accordingly, in a case where it is required to impart mechanical strength such as abrasion resistance to the substrate surface, it is required to provide a hard coat layer on the substrate surface, which makes the process complicated.